ML20033A396
| ML20033A396 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 11/20/1981 |
| From: | Breezeel P ILLINOIS POWER CO. |
| To: | |
| Shared Package | |
| ML20033A391 | List: |
| References | |
| NUDOCS 8111250322 | |
| Download: ML20033A396 (10) | |
Text
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A STUDY OF THE NECESSITY TO PERFORM AN ODYN REANALYSIS
' ON CLINTON POWER STATION t
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4 Illinois Power Company July 9, 1981
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P. G. Breezeel Staff Engineer l
Revision 1
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8111250322 8111d5 PDRADOCK05000g 11/20/81
-PURPOSE
'The purpose of this study.is to compare the Clinton Power
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Station (CPS) ' and the RiverBend Nuclear Power -Station (RNPS)
-reactors to determine whether they are sufficiently identi'-
cal to ' justify the application of the RNPS ODYN transient
~
analyses to CPS.
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BACKGROUND
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ODYN and REDY are both: computer codes developed by-General Electric (GE).
The CPS-FSAR Chapter 15 transient analyses haye.been performed using results from the REDY computer. code.
The Nuclear-Regulatory Commission (NRC) is now accepting the use of
-the ODYN computer code for pressurization transients.
Table 1 shows the seven most limiting transients for CPS.
RESULTS (Part I - d CPR)
The parameters listed in Table 2 are those parameters which are significant regarding the transient events under consideration in this report.
A comparison of the data in Table 2 shows that RiverBend Nuclear Power Station and CPS differ in only four parameters.
A dis-cussion of these differences is given below:
Reactor vessel size - The difference in reactor vessel size is six inches in the height of the vessel.
Since the diameters are the same, this six inches would only make a difference of 0.7% in the vessel volume.
This difference is not significant.
Turbine Bypass capability - The 35% turbine bypass capability for CPS means that any transient involving turbine bypass will be less severe for CPS than for RNPS.
SRV discharge capacity - The difference in the SRV discharge capacities is small but will result in a small reduction in severity for CPS during any transient in-volving an SRV discharge.
Rated void fraction - The difference in the rated void fraction is approximately one percent.
This one percent difference is not large enough to be considered signifi-cant in the calculation of ACPR.
Of the four differences discussed above, the only significant difference is the Turbine Bypass Capability.
This difference is conservative for CPS if the RNPS results are applied to CPS..
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The RNPS-FSAR Chapter 15 transient analysis has been per-formed using'the CDYN code.
A' comparison of the RNPS--
ODYN aild CPS-REDY results for the transients shown in Table-'1 is given'in Table 3.
Regardless of whether the REDY analysis.or ODYN analysis results are used, the limiting transient, in terms of I'
oCPR, remains the Loss of Feedwater Heater with Manual Flow Control (LFHMFC).
The LFHMFC is a relatively' slow transient which does not result in a significant pressure Rev.-1 increase and is therefore not analyzed by~0DYN.
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RESULTS (Part II - Reactor -Vessel Peak Pressure)
'The parameters listed in Table 2:are also significant regarding the peak reactor vessel pressure: transient.under consideration.
in this report (MSIV closure-flux scram).
The comparison of the Table 2 data provided in Part I -ACPR is also applicable to the peak reactor. vessel pressure transient.
4 The peak reactor vessel pressure.for the MSIV closure-flux scram transient for CPS'(predicted by REDY) is shown in Chapter 5.of-the CPS-FSAR as approximately 1300 psig.
The~ peak reactor vessel o
pressure for the'MSIV closure-flux scram transient'for RNPS
~
(predicted by ODYN) is shown in Chepter 5 of the RNPS-FSAR as l
approximately 1270 psig.
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FINDINGS An ODYN analysis has already'been performed for the RNPS and an ODYN analysis for the CPS would yield the same, or less severe results, as this already completed analysis.
There are no detrimental safety or operational implications if the RNPS ODYN analyses is used-for CPS because:
a.
the limiting ACPR-transient will remain the LFHMFC which is not analyzed by ODYN and b.
the pressure for the limiting peak. reactor vessel pressure transient is less than the peak pressure predicted by REDY for which CPS is already analyzed.
Based on the information presen'ed in this report, an ODYN t
analysis on Clinton need not be -performed.
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. Table 1~
'The Seven Most Limiting Transients for CPS 1.
' Load Rejection Without Bypass, 2.
Load Rejection With Bypass,
--3.
Feedwater Control'. Failure, 4.
Loss of Feedwater Heater with Manual Flow Control, 5.
Turbine Trip Without Bypass, 6.
MSIV Closure - Flux Scram,.and o
7.
Pressure Regulator Down Scale Failure.
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7 CONCLUSION The Clinton Power Station and the RiverBend Nuclear Power Station are very nearly identical as far as parameters significant to the seven transients listed in Table 1 are concerned. 'Any differences in the CPS and RNPS design will result in less severe consequences for CPS.
Therefore, for a given transient the results of an ODYN analysis performed on CPS would necessarily be the same, or less severe, as the ODYN analyses performed on RNPS.
Since a CPS-specific ODYN analyses would be the same, or less severe, for a given transient than the RNPS ODYN analyses, the RNPS ODYN analyses would be conservative when applied to CPS.
Even though the OCPR results of a given transient may differ between the RNPS ODVN analysis and a CPS ODYN analysis (if performed), the limiting transient would remain the same.
This limiting transient would not change because it is not required to be analyzed by ODYN.
Rev. 1 6-
Table 2 i
CPS vs. RNPS Parameter Comparison Parameter CPS RNPS Reactor Type BWR-6 BWR-6 Reactor Vessel 1.D.
218 in.
218 in.
Reactor Vessel Size 18'2" x 69'4" 18'2" x 69'10" Steam line volume 3275 ft3 3275 ft3 MSIV closure time 3-5 sec 3-5 see Control valve closuretime
.07 sec
.07 see 6
6 Core flow 84.5 x 10 1bm/hr 84.5 x 10 1bm/hr Turbine bypass capability 35%
10%
Scram time fast scram fast scram Power level 2894MW(th) 2894MW(th)
Dome Pressure 1040 psia 1040 psia 6
6 SRV Gischarge capacity 13.9 x 10 1bm/hr 13.6 x 10 1bm/hr Fuel Assemblies 624 624 Recirc. pipe size 20 in.
20 in.
Stop valve closuretime
.1 sec
.1 sec Void reactivity power increase
-14c/% void
-14c/% void power decrease
-4c/% void
-40/% void 6
6 Steam flow 13.07 x 10 1bm/hr 13.07 x 10 1bm/hr Core leakage flow 11%
11%
Core safety limit first core 1.06 1.06 reload 1.07 1.07 Doppler coefficient
.132c/0F
.132c/0F Total scram reactivity
-$37.05
-$37.05 SRV setpointc low pressure group 1 viv. 1103 psi 1 viv. 1103 psi medium pressure group 8 vivs. 1113 psi 8 v1vs. 1113 psi high pressure group 7 vivs. 1123 psi 7 v1vs. 1123 psi APRM setpoint 118.8% NBR 118.8% NBR Max Feedwater flow 3631 lbm/sec 3631 lbm/see Rated void fraction 43.08%
42.53%
Feedwater temperature 4200F 4200F Relief valve characteristic sensor and logic-delay
.3 sec
.3 sec valve delay.
.1 sec
.1 sec valve stroke time
.15 see
.15 see Safety valve characteristic valve stroke time
.3 sec
.3 see
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